Improvement in sanding-machines



o. s'AWYEYR, A. & H'. c. KNoWL'roN.

SANDIN'G-MACHINE.

Patented May Z, 1876.

N. PETERS. FMOTO-LITNOGRFHEH. WASHINGTUI'. D C.

oLivEE s AwYEE, on wiNeHENDoN, AND AUeUsTUs KNowLroN AND HENRY.ogKNowLroN, 0E GARDNER, MAssAoHUsETTs.

l IMPROVEMENT IN SANDlNG-MACHINES.

Specification forming part of Letters Patent No. 177,018, dated May 2,1876 application led October 19, 1875.

To all whom yt may concern:

Be it known that we, OLIVER SAWYER, of Winchendou, and AUGUSTUS KNowLToNand HENRY C. KNoWLToN, of Gardiner, Yin .the county of Worcester andState of Massachusetts, have invented certain Improvements inSanding-Machines, of which the following is a specification In theaccompanying drawing, forming a part of this specification, Figure lrepresents an end elevation oi'a machine embodying our invention; andFig. 2 is a front elevation of the same.

rlhis inventionlrelates to that class of smoothing or sanding machinesin which a belt coated with sand or emery is employed for smoothing datsurfaces, the belt being supported, at the point where it operates onthe stock, by a pulley having an elastic periphery. l

The invention has for its object to provide means whereby pieces of datstock of differerent degrees of thickness can be presented to thesmoothing-belt at the point where it is supported by the elastic pulley,and sanded on one side alone, by the employment of ene smoothingbelt, oron both sides simultaneously, by the employment of two smoothingbelts.To this end oui` invention consists in the combination of feed-rolls andsand-beltsupporting pulleys, which we will now proceed to describe, andpoint out in our claim.

In carrying out our invention we employ a frame-work, A, adapted tosupport the oper ative parts of our invention. Bv represents a beltcoated with sand or emery in the usual manner. P D represent the pulleyson which the belt is supported and driven. The pulley P we term thebearing-pulley, the same being located in such relation to thefeed-rolls hereinafter described as to constitute a bearing or supportfor the belt Bl at the point where it operates on the stock presented toit by said feed-rolls. The periphery ofthe bearing-pnl ley is made ofany suitable yielding or elastic material-such as cloth, rubber, Ste-andforms a bearing for the belt B sufficiently Vyielding' to prevent thecoating ot' the belt from being held positively against the surface tobe sanded. R R R' R' represent feed-rolls,

which are preferably rubber-coated, and arelocated with their axessubstantially parallel with the axis of the bearing-pulley P. Thesefeed-rolls are arranged in such relation to the bearing-pulley P that apiece of stock passing between them will be subjected to the action i ofthe belt B at the point where it is supported by said bearing-pulley.The rolls R' lt' we prefer to locate in yielding bearings, so as toadmit ot' the introduction of pieces of stock of different thicknessesbetween said rolls and the rolls R R, whose bearings are stationary,suitable devices being employed for imparting a yielding pressure to therolls R' R' in the direction of the rolls R R, as will be hereinafterdescribed. The motive power may be applied to either of the pulleys P D.We prefer to connect the bearing-pulley' P to the prime motor, andlocate the pulley D in a swinging frame, F, which is provided with aweight, W, the latter tending to draw the pulley D away from the pulleyP, and thus tighten the belt.

It will be seen that a dat piece of stock presented by the feed-rolls tothe belt in a direction at right angles with the axis ot" the bearing-pulleywill be acted on uniformly by the supported portion ofthebelt,the stock bein g passed along by the rolls until it is sanded fromend to end. The elastic peripheryof the bearingpulley prevents the rapiddestruction ofthe coatiugof the belt which would result if the pulleyhad a rigid periphery.

We have thus far described an adaptation of parts for sanding one sideoi' a flat piece of stock at a time. For operating simultaneously onopposite sides of a flat piece we employ an additional belt, B',bearing-pulley P', and tightening-pulley, D', these parts beingsubstantial duplicates of thebelt B and pulleys P D, and so located asto cause the belt B' and bearing-pulley P' to assume the same relationto the feed-rolls It' lt' that the belt B and pulley P sustain to thefeed-rolls It R, the belt B' being thus caused to operate on one side ofthe stock, while the belt B operates on the opposite side, the axes ofthe pulleys being parallel. rlhe pulley P' and feed-rolls R' R' havetheir bearings in a block or carriage, C, which is adapted to slidevertically in suitable ways. T is a weighted arm or lever, which exertsan upward pressure on the car e V nuns riage C and its attachments, andholds the' bearing-pulley P' and belt B with a yielding l pressureagainst the stock to be smoothed, thus adapting the machine to operateon stock of` dierent thicknesses. The tightening-pulley D' is journaledin a swinging weighted frame, F', which operates 'substantially liketheframe F of the pulley D.

By this invention we are enabled to rapidly, economically, and uniformlysand pieces of stock having flat surfaces, and of dierent'de grees ofthickness.

We do notlimit ourselves to the employment of both beltsB B', as eithermaybe dispensed with, if desired; neither do We limit ourselves` -l tothe employment of the tightening-pulleys D D', as any suitablearrangement of pulleys may be employed in connectionwvith the elasticbearing-pulleys and any suitableI heltltight- .i `i ening devices may besubstitutedfor the swingl ing weighted framesfwithout departing Vfromthe spirit of our invention.

We claim- In a sanding machine,- the combination of the feed-rolls B R,located in fixed bearings, and thefeed-rolls R' R', located inyieldingbearings, with the pulley P locatedin fixed bearings, andsupporting the sand-belt B, or with i thepulleys P P'located,respectively, in fixed fand yieldingbearings, and supporting the belts BB', substantially as described, for the .Purposes specified.

Intestimonywhereofwe have signed our names to this specication in thepresence of two 'subscribing Witnesses.

OLIVER SAWYER. AUGUSTUS KNOWLTON. HENRY C. KNOWLTON.

Witnesses THATCHER; B. DUNN, JN0; ,4 HEYWooD.

